Sure, that's not a problem. DO you know what your router's IP address is? Usually something like 192.168.1.1
Do you have any other computers connected to the router? What are their IP's? Usually something like 192.168.1.2, 192.168.1.3 etc, etc
You want to know all of that so that you don't give the laptop an IP that is already taken. Also, what brand and model of router are you using?
To tell the laptop to ask for a specific IP address do the following:
Start > Network Connections > Right click the Wireless Connection > Properties > Scroll down to Internet Protocol (TCP/IP) > highlight it and choose properties.
Check the radio button that says use the following IP address > Enter an ip address for your Laptop, ex- 192.168.1.5 > subnet mask should be something like 255.255.255.0 , You can confirm that in your routers configuration page > Default Gateway is the router's IP address, ex- 192.168.1.1
Also, check the radio button that says use the following dns server addresses. Your ISP should have their DNS servers listed on their help site somewhere. You do not have to use theirs, you can use any one you want. I posted two here for you to make life easy.
Preferred DNS Server - 184.108.40.206
Alternate DNS Server - 220.127.116.11
Click OK when you are done and try to connect to your wireless network again. Let us know how this works for ya.